THE BASICS OF
The steps to achieving a good bike fit are few and easy. First, you must
decide which style of geometry is for you. Against the backdrop of some
immutable rules that apply to every position you choose, you're free to
ride however you want. You can ride with a seat angle of 74 degrees or
with 81 degrees. There is no necessarily perfect or special, or even
tri-specific geometry to which you ought to aspire.
Each of the three riders represented at top are in a position that is
appropriate for triathlon racing. One immutable rule is that the range
of motion in which your thigh musculature operates ought to be biomechancially sound. We might roughly refer to a "hip angle" that is
formed by using the bony protrusion of your hip (greater trochanter) as
the apex, and with that angle's lines being: 1) one that run from the
hip to the foot, and, 2) from the hip to the bony protrusion of the
That hip-to-the-foot line is a little tough to nail down. Ought it to be
from the hip to the bottom bracket? Or to the maleolus (bony protrusion
of the ankle)? Or to the pedal axle? If so, where? At the bottom of the
pedal stroke? With the crank in line with the seat angle (or relative
seat angle)? If it's the hip angle you're measuring, why measure the
angle in its most obtuse configuration? Why not at its most acute, when
your foot is at the top of the pedal stroke?
All these are valid observations, but it doesn't much matter. If the
proper bike fit is in fact proper, it doesn't matter where you measure,
but each of these lines formed by the proximal point (hip) and the
terminus at the line's distal point (ankle, BB, pedal axle, whatever) is
going to change depending on which distal point you choose. I personally
favor the pedal axle at the bottom of the pedal stroke, and my
definition of "bottom" (for the purposes of measuring this angle) is not
at 6 o'clock, but at the point where the axle is in line with the seat
angle is 90-95 degrees, and while I don't like angles more acute than
that, I don't mind a more obtuse angle, up to a point. I can in some
cases live with 100 degrees. I have a problem living with an angle
greater than that. As long as this is your hip angle, however, it
doesn't matter to me whether you're riding at 71 degrees or 81 degrees
of seat angle. Realize, however, that as you rock yourself back
in the saddle you're rocking yourself up in front, that is, your back
will not be as flat and you will probablybe punching a larger hole in
the wind as you propel yourself forward.
Why would one want to be less
Comfort, plain and simple. Rotating one's body complex forward means
you're no longer sitting on that padded place God provided for you.
You're now resting on the saddle in places God did not intend in his
infinite wisdom for you to rest. Perhaps the Grand Design did not
When one rocks all the way back—the Green Rider—this is a road race
position, and a proper road bike fit is easy to achieve. By “road bike”
I’m talking about no aero bars on that bike.
If you’re a triathlete, however, you no doubt feel compelled to have
triathlon bars on your bike. You shouldn't. Not necessarily, at least.
There is nothing wrong with riding—even while racing in a triathlon—on a
road race bike with road bars, STI or Ergopower shifting, and no aero
bars whatsoever. In fact, if you're new to the sport, that's probably
the best choice you could make, especially if you're brand new to STI-style
shifting and clipless pedals, and if you've never before ridden with tri
bars. All that is hard to learn in one fell swoop.
Besides, in another month, or two, or six, you can bring your bike into
the shop and have aero bars retrofitted onto this bike. This is easy,
it's just a pair of clip-ons, and it takes 15 minutes to add them. If you
add full aero bars, however, you may find that that perfect road bike
fit doesn’t work anymore now that you’ve laid your body down on the
apparatus that essentially turns your bike into a front recumbent.
The keys to
a good fit while on aero bars are few, and easy to grasp. There is now a
second angle with which to be concerned, and as is the case with the hip
angle above, this second angle is not an angle on a bike—but one formed
by your body. Remember that line running from your hip to your shoulder?
Now imagine a line from your shoulder to your elbow. This “shoulder
angle” formed between your torso and upper arm also ought to be 90
degrees. Achieve this angle and you’ll be comfortable.
(A NOTE ON MEASURING ANGLES: Finding the proper point on your
shoulder can make these angles tough to measure, and the points differ
depending upon which angle I'm measuring. I find that when measuring the
hip angle the line ought to pass from the greater trochanter through the
shoulder, and through the collarbone which, while in the aero position,
will be in front of the shoulder. But when you're figuring your shoulder
angle, the line representing the upper arm ought to pass through the
centerline of the arm midway from front to back. The intersection of
these two lines represents the apex of the shoulder angle being
The problem with sticking full tri bars on your “perfectly fit” road
race bike is that the bike is too long for these bars or, if you prefer,
the clip-ons are too long for the bike. You’ll notice that your shoulder
angle is greater than 90 degrees. You’re too stretched out. The
solution? Don’t get full aero bars. Buy a shorter bar made just for a
road bike position. There are several out there. Cinelli makes two, the
Spinaci and the Corna. Profile Design makes a very popular model called
the Jammer, and a souped-up version called the Jammer GT.
The good thing about these bars is that they’ll allow you to achieve
that 90-degree shoulder angle without changing the fit and set-up on
your road bike. The negative is that the armrests aren’t hitting you
under your elbows, but under your forearms, almost under your wrists.
That is not optimal for a lot of people.
Enter the “tri bike.” This is a bike built around the proposition that
you’re starting with a full aero bar, and the geometry of the bike is
built around the use of the bar. This bike has a very different geometry
than a road race bike, but the “rules” mentioned above still hold. How
is that so?
picture of a hill climbing specialist riding seated up Mont Ventoux.
Stick a straight pin in his bike’s bottom bracket, and rotate the
picture forward. His rider position won’t change, if you’re considering
the “body angles” spoken of above. If you’re very good with a pair of
scissors, cut out just the rider, separating him from his bike. Now
rotate him forward around the same axis, leaving his bike in place (as
in the photo above). You’ll notice his trunk moves forward relative
to the bike’s bottom bracket. His back gets flatter. He’s assuming an
“aero position.” The only thing we need to do is to place an aero bar
underneath his elbows. And this is what a tri bike is—steeper seat
angle, lower front end, and a shorter chainstay so as to draw the rear
wheel back under the rider’s weight, so that the bike handles
should you rotate this rider forward? It’s up to you. You can ride with
a 73-degree seat angle, typical of a road race bike, more or less. Or
you can ride at 80 degrees, common in a full-blown tri bike offering a
very aero position. Anywhere in between—anywhere along this continuum—is
fine. The steeper your seat angle, the lower your bars can go, that is,
the flatter your back can be.
Realize, however, that there are equipment and configurational changes
that follow each move along the "continuum." As you move back in the
saddle your aero bar armrests ought to be raised higher, and will be
closer in elevation to the level of your saddle height. As you move more
forward, your armrests can be lower, and your back flatter. If you
decide to ride more in a conventional (rearward) road race position,
with road bars and STI shifting, your aero bar's extensions will be
shorter, and your armrests will "move up" your forearms toward your
wrists. The more forward you are, the lower you will be, and at some
point on the continuum (maybe at around 77 degrees of relative seat
angle) you'll want to change from road bars to pursuit bars and bar-end
shifting, and then your arms will rest on the armrests with the pads
more under your elbow than your wrists, and your aero bar extensions
will be closer to full length.
"Why can't I ride my road race bike in a road position AND have full
aero bars AND ride with the armrests under my elbows?" you might ask.
You can. But then you're likely to have a shoulder angle much greater
than 90 degrees, and you'll be uncomfortable. In other words, you can't
have it all, so you'll have to pick which features you want, and which
you'll choose to live without.
WHICH GEOMETRY STYLE IS RIGHT FOR YOU?
In the beginning of my remarks I wrote, "You must decide which style of
geometry is for you." How do you decide that? When a person comes to me
for a bike fit, I ask a variety of questions, such as:
Do you have
only one skinny-tired bike, or will you own both a road race bike
and a tri-specific-geometry bike? |
intending to road race on this bike, or commute, or do centuries and
group rides with road riders? |
Do you intend
to spend a lot of time in the aero position, or only be there very
is speed to you? (This is not a rhetorical question, there are
plenty of people for whom the finish time is not especially
I will also
attempt to ascertain how athletic this person is, and how high the
effort level is likely to be during the bike leg of the race. I'll
consider the person's morphology—someone who is carrying a lot of extra
weight is going to have that weight coming down on the saddle and
whatever place on one's anatomy is in contact with the saddle.
Something must be understood about a full-blown aero position. It is
most comfortably ridden while under a fair amount of power and effort.
Riding an exceptionally easy (perhaps recovery) ride is less pleasing in
the aero position than on a road race bike. The easy solution is to have
two bikes, which I do. But not everybody does, or at least they don't
while still new to the sport. But that does not lessen the realities of
which position is best for which style of riding.
Having an an aggressive, aero position for riding to Starbucks for
coffee is like commuting to work in the city using a Ferrari. Sports
cars are nice, but a Caddy is perhaps better for stop-and-go traffic.
How often, and for how long at a stretch, will you be riding with effort
in the aero position? That answer to that question will determine where
along the continuum from shallow to steep you ought to be.
For this reason, I usually recommend a road race bike as one's first
enter into tri-bike ownership. This bike is easy to ride, and the
position is accessible to just about anyone. It's a better bike on which
to learn click-shifting, clipless pedals, and the beginnings of riding
in the aero position. It's a better bike for corning and descending. It
may end up being the only style of bike you'll ever own for triathlon.
And if you do migrate to a tri-specific bike, you'll still use your road
bike for group rides, recovery rides, early season riding, and so forth.
that, there is one other option. Consider the "pink" rider at
That might be what we could term a "multisport" position, and is just a
bit of the way forward in the continuum. One could achieve that position
by retrofitting a road bike with short aero bars and moving a few
centimeters forward, or by having a slacker-than-usual tri-specific
bike. For that person who is looking to spend not too much money and who
wants a bike built just for the "multisport" position, however, this
category of multisport bike is gaining in popularity.
The one thing to
remember is that shallower-angled road and "multisport" bikes are best
ridden with road bars and road-style shifters and brake levers. Choose a
handlebar set-up which is appropriate for that point along the aero
continuum with which you’re comfortable. Will you be riding in a road
race position, at 72 to 75 degrees of seat angle? Choose road race
(drop) bars with STI-style shifting and clip-ons. Are you going to be on
a steep seat angled rocket? Choose pursuit bars and bar-end shifting.
WHY MUST SEAT ANGLES MATCH FRONT END CONFIGS?
I'm not very patient with bicycle manufacturing companies. They ought to
know how to build bikes correctly, and you'd think that if they were
going to spend a million dollars or more on a line of bikes for
triathletes, they'd take the time to get it right. Unfortunately, it's
common to have no one in these companies who actually ride tri bikes;
neither do these companies' product managers seek valuable information
or guidance during the design the process. If anything, they ask their
dealers what they want. This is often the blind leading the blind.
The simple way to view it is this: If you're going to ride a traditional
geometry, ride the bars that traditionally go with it (road race bars).
You contact the bike in three places—where the bike meets your hands,
your butt, and your pedals. These three places must be properly
spatially related to each other, and they must allow the body to form
the two 90-degree angles mentioned in the sections above.
There is a reason that full tri bars don't make sense on a
shallow-angled tri bike, and it is related to your shoulder angle. When
you're on a properly-fit road bike, and you're riding in a road
configuration—73 degrees of seat angle, road bars, STI, etc.—and when
your hands are on the hoods, you have something close to that magic
90-degree angle (when you're low and really going hard, with your
forearms parallel to the ground). When you put a full tri bar on your
bike, the clip-on's extensions reach considerably further forward than
the forward protrusion of the hoods. If you extend all the way, and your
hands grab the extensions' ends, your shoulder angle is much greater
than 90 degrees. You're too stretched out. In order to achieve that
90-degree angle, you'll have to have a shorter clip-on—either a very
short size of a full clip-on, or a model of "shorty" clip-on with
shorter extensions by design.
Of course you could also achieve that 90-degree shoulder angle by moving
your saddle forward instead of by moving the clip-on extensions back.
Nothing wrong with this, except as you keep moving forward you've got
more and more weight on the front wheel, and this can cause handling
problems (hence the tri bike). Forgetting that for a moment, your
saddle's movement forward also allows your aero bars to move lower in
elevation, that is, you're allowed to make yourself more aerodynamic.
Now you've got quite a different position. Your saddle is forward in
relation to the bottom bracket, and your road bar's hoods and drops
positions are now much closer to you, and they're sitting much lower
than the saddle. Your "points in space" are very different in relation
to the saddle and to the bottom bracket. They don't work anymore.
Enter the pursuit bar. The idea is to re-create the position formerly
inhabited by your hoods, i.e., before you lowered your road race bars to
make yourself more aerodynamic. The irony is, people are fain to give up
their road bars because they covet their hoods position. But when you
lower your bars, you may keep your hoods, but you lose your favored
hoods position (and you entirely lose your drops
position). The only way to maintain your hoods position is to
dump the hoods, and the bars on which they're mounted, and go to a flat
pursuit bar. Then you'll regain (something close to) your hoods
I'm often asked about the utility of having STI shifters on a pursuit
bar. I don't like this, because of the technical way a forward tri
position ought to be ridden. For now I'll reiterate that this is a position
which must be ridden at a high cadence—no lagging, or mashing. The need
to shift often is paramount, and having the shifters where your hands
are is critical.
There are three ways to determine saddle height. Method Three is the
subjective method—adjust it until it feels right. This is really the
ultimate eventual way. After you utilize objective methods One and Two,
you'll always come 'round to Method Three. But you shouldn't start there
and besides, your ability to correctly apply Method Three depends upon
whether you're body aware and untuitive, and some people are just
body-deaf (or whatever the body-awareness-analog is to "tone-deaf").
This leads us back to the objective methods. Method One is to use a
multiplier of one's inseam. Stand on the ground, straight-legged, and
place a book up into your crotch, about where you figure the saddle will
rest. measure this distance to the ground. Multiply this by .885. Some
people use .883. Personally, I don't like this method, because of the
imprecision of where the crotch actually is; and where to measure to on
the saddle's top. I also think that for steep seat-angled tri bike
riding the saddle ought to be slightly higher than for road riding. This
remains, however, the predominant way to measure saddle height.
Method Two is to consider the knee angle when the pedal is in its lowest
position. But first there are a few things I need to make clear. There
are two places on the foot to which you're going to measure. When you're
determining the location of the bottom of the pedal stroke, this
is measured to the pedal axle, and while the differences are
minute, and for the purposes of measuring knee angle, I don't like to
consider 6 O'Clock the bottom of the pedal stroke. I rather prefer it to
be that point where the crank arm is parallel to the line drawn up to
the greater trochanter (i.e., more or less parallel to the seat post).
If you consider the red line in the adjacent diagram, this is the
position in which the knee angle ought to be measured.
But once your leg is in this extended position, you'll now start
measuring to a different area. When determining knee angle you're
measuring to the maleolus.
Using the bony protrusion of the outside of the knee as the angle's
apex, draw a line to the greater trochanter (bony protrusion of the hip)
and to the maleolus (bony protrusion of the ankle). The angle formed
ought to be either 145-150 degrees, or 150-155 degrees, depending on
whom you talk to. For road riding, I think 150 degrees sounds pretty
good. For tri bike riding I like it closer to 153-155 degrees. Perhaps
increasing the angle one degree might be roughly equivalent to
increasing the saddle height by one millimeter, though it's going to
differ depending on the height of the rider.
The tricky parts of calculating saddle height by Method Two are: 1) you
really need a second person to do this; and 2) your pedaling technique
is going to effect this—if the aspect of your ankle is not correct
during the pedal stroke it can cause your seat height measure to be off.
If, for example, you're pedaling too much with a "toes down" aspect—if
you have to stretch to reach your pedals—you might think your seat
height is correct by virtue of your knee ankle when in actuality your
seat would be too high.
On the other hand, the nice thing about this method is that it takes
into consideration the height of your cycling shoe, pedal and cleat,
where you sit on the saddle, any shims that correct for leg length
discrepancy, and your crank length. It also takes into consideration any
influence exerted by your pedaling technique. So I guess I like this
What do I mean by "influence exerted by your pedaling technique?" I tend
to ride with a fair amount of "heel drop." I also seem to read that heel
drop, or lack thereof, is a matter of personal preference. Fair enough.
But whatever your preference, it's going to make a difference in your
saddle height. If my heel is dropped more than yours at the bottom of
the pedal stroke my saddle needs to be slightly lower in order to
maintain this 150-155 degree knee bend.
What influences heel drop? Your power application throughout the pedal
stroke, your desire to utilize your calf muscles—a somewhat
insignificant muscle group in pedaling, but of some utility—and your
cleat mount (the more forward your cleat, the more you can recruit your
DETERMINING WHICH POSITION IS BEST
Now we get to the meat of it. This is the most difficult part, and if
you're a bike fitter it's the part requiring the most skill, in my view.
I don't mean the act of executing a proper tri bike fit on, say, Tim
DeBoom or Peter Reid. That's easy. That takes 20 minutes, or ought to.
The skill comes in determining whether a subject ought to be positioned
like Peter Reid, or on a road race bike with STI and shorty clip-ons, or
somewhere in the middle. And if it's in the middle, where in the middle?
The hard part is figuring out just how aggressive one's position ought
to be and can be. The devil of it is, you can be positioned at 74
degrees of seat angle, 76 degrees, 78 degrees, and at 80 degrees, and in
each of those positions you might feel great. If you are positioned too
shallow, might you've gone faster if you were positioned more steeply?
If you're set up steeply, what will you feel like after three hours in
the saddle? I believe the art and science of tri bike fitting ought to
be light on the art and heavy on the science—but if there's a place for
art, this is it.
The goal is to get you as close to 80 degrees of seat angle as possible.
The reasons for this are two. There is the lower metabolic cost
associated with riding further forward. By "lower metabilic cost" I mean
less recruitment of fast twitch fibers during the pedal stroke, leading
to a lower rate of glycogen consumption at a given power output (fast
twitch fibers consume glycogen at a rate 50 percent greater than do slow
twitch fibers). I admit that it takes a short leap to come to the
conclusion at which I've arrived—a tieing together of studies to make a
Then there is the aerodynamic benefit associated with being able to ride
lower in front, which is linked with riding forward (it's hard to ride
low if you don't move forward). This requires another leap of faith.
It's my assumption that by having one's handlebars lower rather than
higher that the result will be a position exhibiting better
aerodynamics. Surprisingly, even this is not universally agreed upon.
But we'll assume this as axiomatic, and for those who don't believe that
lower in front almost always means a lower coefficient of drag, we'll
just have to agree to disagree.
Though a lower front end might mean lower drag, it doesn't necessarily
mean a lower finish time. There are four mitigators, and each of these
mitigators serves to cause one to sit further back than 80 degrees. The
major one is comfort. If you can't maintain the position comfortably for
the duration of your race, what good is it? In this case it's better to
be more rearward. This will mean you'll also be a little higher in
front. You'll sacrifice a little bit of aerodynamics. So be it. You'll
be better off in the long run (pun intended).
The second mitigator is the "M-factor" and "M" is for Mystery. Yes,
Peter Reid, Cameron Brown and Tim DeBoom ride quite steeply. But Cameron
Widoff doesn't. Yes, Craig Walton rides steeply—very steep, if you
consider not just his bike set up, but where he rides on top of the
saddle—yet his countryman Chris McCormack doesn't. Natascha Badmann and
Paula Newby-Fraser ride steeply, but Heather Gollnick doesn't. While
three-fourths of the world's best triathletes ride steeply, 20-25
percent don't. Why? Is it because they don't know any better, or because
they just haven't been set up in a correct steep position?
I don't think this gives them enough credit. I rather suspect it has
something to do with levers and musculature. I don't believe riding with
a steeper seat angle gives you more power at the same heart rate (a
claim I've seen), but I do believe it gives you equivalent power
and heart rates while spreading the work around to both anterior and
posterior thigh musculature during the pedal stroke. Let me use an
Imagine a company with too few workers and a lot of work to perform.
Some of their employees have to work overtime, and the company must pay
time-and-a-half. If they hire a few more employees, the work gets spread
around, and the company doesn't have to pay overtime. Let's say,
however, that it's the best, strongest workers who're getting overtime
pay. Do you hire more workers or pay overtime to the strongest workers
you've got? This is the dilemma. Most triathletes find that more
employees is the better solution, and as a result everyone on the job
has more energy for happy hour after the evening whistle ("happy hour"
being the "run" in my metaphor). For some athletes, though, I think
evening the work throughout the thigh muscles isn't playing to their
strengths. I don't entirely know why.
The third and fourth mitigators have nothing to do with anyone reading
this, but I'll mention them anyway, because the subject comes up. There
are two reasons Lance Armstrong doesn't ride with a steep seat angle.
The first one is, he'll get kicked out of the Tour de France if he does.
The rules won't allow it. If your racing was governed by these rules,
believe me, you would know it. Only bike racers fall under these rules,
and even then not one percent of the bike races in the U.S. are subject
to UCI rules. But even if the rules did allow Lance to ride more forward
in the time trial, I don't know that he would. There is a risk
associated with changing one's riding style for one or two days
sandwiched in between the 20-odd days of a grand tour. I suspect that's
a risk some grand tour riders are unwilling to take. Keep two other
things in mind when using Lance's riding position as a model. First,
he's not running off the bike. Second, in his "former life" he did win
two national triathlon championships on bikes I provided him—both
80-degree seat angled bikes.
Contemplate the diagrams above, and realize that anywhere along the
continuum from 74 degrees to 82 degrees of seat angle are fine. However,
there are rules you must obey. First, those two 90-degree angles written
of above must be preserved. Second, the more rearward you are the more
appropriate are road bars, STI, and a shorter clip-on. The more forward
you are, the more pursuit bars and bar-end shifting start to make sense.
Where ought you to be along this continuum? All things equal, the
younger, leaner, fitter and lither you are, the more forward you'll want
to ride. Also, the shorter the race the more you'll probably want to be
forward. If you ride with lesser effort, if you carry more weight, if
you're older, if you race a longer distance, and if you're more of a
mesomorph (strong, muscly-type) the more you're likely to tend toward a
position back from 80 degrees.
Where you eventually ought to end up depends on your subconscious
tendencies while riding. Do you always seem to be scooting forward in
the saddle? Are you sure it isn't because you're too stretched out, and
you're subconsciously trying to "achieve" that 90-degree angle between
your upper arm and torso? If you're riding on the saddle's nose in spite
of having a proper cockpit distance, you're probably positioned too
shallow. Are you always pushing yourself back in the saddle? Are you
sure it's not because your saddle's nose is tilting down (a bad idea, by
the way), causing you to have to push yourself back because you're
sliding forward? If you're almost always sitting on the rear of a
level saddle, perhaps you're too far forward. Are you frequently out
of the aero position? Again, you're probably too low in front and too
far forward—while it's a position that might feel good for short spurts,
if you can't maintain it for the duration of the ride, you're just too
aggressively set up.
A NEW FORMULA
FOR SLACKER-ANGLED ARMREST DROP?
I have a formula for armrest drop, and it is this:
causes a lot of hand wringing, because people just read it and try to
conform to it, without following the "rules" that are associated with
it. But first, I'll explain it.
Distance "C" is what we're looking for, and it is the distance in height
(in a vertical plane) between the saddle and the armrests. If you were
to drop a line from the top of the saddle to the ground, and measure it,
and then do the same with the armrests, the difference between these two
numbers would be the difference in height between the saddle and the
armrests. The easiest way to measure it, I think, is to lay one end of a
carpenter's level on the saddle, and angle the level over one of the
armrests. With the bubble in the middle of the level (i.e., with the
level parallel to the ground), measure from the bottom of the level to
the top of the armrest with a ruler.
is that we've already got the seat height established, via the
guidelines in a chapter above. We've also got the "cockpit distance"
more or less established, that is, the distance from the nose of the
saddle to the ends of the clip-ons, because that distance is whatever it
needs to be in order for our upper arm and torso to achieve a 90-degree
angle. You've then raised/lowered your bars so that your "hip angle"
achieves a 90-degree angle, or perhaps 95-degrees, and by virtue of that
we don't really even need a formula for armrest drop, because the drop
is whatever it needs to be in order to achieve the proper hip angle,
right? So, why do we even have a formula for armrest drop?
Only as a
double-check. If, after you've positioned yourself properly, you plug
your saddle height into the formula and you get a number WAY off from
the range indicated by the formula, then you've got to ask yourself why.
Perhaps there is a perfectly appropriate answer. Either way, that's what
the formula's for—it's just a double-check.
But there are rules and assumptions:
• This formula
assumes that you're a very fit, well-trained athlete in mid-season form.
• This formula applies to a position all the way forward along the
continuum, which for me means something in the order of 80 degrees of
relative seat angle. If you're positioned at 76 degrees and you try to
apply the formula above, you might find that the position is too
aggressive and—guess what?—you'd be right. You don't have a steep enough
angle to justify a drop of that degree.
Here's how it
would work, and I'll use myself as an example—I'll present the formula
again below for reference.
I ride with
about 79cm of seat height (distance "D" in the formula above). That
quantity, squared, times .005, equals 31.2. Subtract 79 X .2 (which
totals 15.8) and you get 15.4. Subtract 1.5 and that equals 13.9 (we'll
call it 14)—and realize all these calcs are in cms. The fudge factor is
1.5cm in either direction, so my armrest drop could range anywhere from
12.5cm to 15.5cm. It is in fact about 13.5cm.
I admit, however, to having a more aggressive seat angle than most (I
ride with 80°). What about those who'd like to ride at perhaps 78°, or
76°? What ought their drop be? While I'm not convinced of the utility of
this, I'm working with a coefficient-based adaptation of the formula
above, where ".2" above increases by 075 for each degree shallower than
80° you'd ride. So, if you rode at 79° the product would be (.2075D),
and if you rode at 78° it would be (.215D). Here's the calc for someone
riding at 77°:
In this case, if I were to use myself as an example (and if I haven't
made a mistake) the drop for me at 77° of seat angle would be about
12cm, and the range would then be 10.5cm to 13.5cm. In other words, if I
slackened my seat angle by 3°, I'd probably have to raise my bars about
2cm, more or less. You can see why this would be the case. If I don't
raise my bars when I slacken my seat angle, my hip angle will become too
Perhaps adding this whistle to my formula will prove efficacious, though
it's too early to tell. I hope, at least, that you see the point, which
is that you can't take any of these features—seat angle, armrest drop,
clip-on length, base bar type—and consider them in a vacuum. They all
must make sense as a construct. I hear, every now and then from
retailers, that my formula represents a front-end drop that is too low
for the bulk of their customers. Maybe it's because the rest of the fit
is bad. Or maybe it's because it's being applied to customers who're
being set up at 76 degrees of seat angle. If one takes into
consideration the limitations of this formula in its raw form, then
perhaps it appears less formidable.
HOW TRI-SPECIFIC GEOMETRIES MUST BE RIDDEN
This topic is not specific to tri bike fit, strictly speaking, but it
deserves mention. If your retailer sent you and your mate out the door
on a tandem, he'd be well advised to give you a tip or two if you were
tandem virgins. Likewise, it ought to be pointed out that your riding
experience on a tri-specific bike is not going to be 100 percent
positive if you don't take advantage of the strengths of this bike.
By "this bike" realize what I'm going to present below assumes that
you're on a tri-geometry bike, riding with a seat angle of 77 degrees to
81 degrees. The shallower you are—76, 75, 74-degrees—the less this
section refers to you. In fact, if you're riding below 75 degrees of
seat angle it doesn't refer to you at all.
There are just three things to remember, and these points ought to
govern your tri-geometry riding.
• This is a position which optimizes the use of lay-down,
tri-specific handlebars. Any time you're in the aero position,
you're on a better bike than a road race bike. Whenever you're out of
this position, you'd have been better off on a road race bike.
Therefore, you better like your position, and be prepared to be in it
almost all the time.
Imagine skating around an ice rink. What is your intent? To skate
quickly, and perhaps race? A nice, long pair of speed skates is made for
the purpose. But what if you want to just knock around with the guys
occasionally? Jump into a hockey game now and then? Do a few pirouettes?
Or just tool around at an easy clip? Clack skates aren't made for that
purpose, and you'll find them unwieldy. Likewise, a steep tri-geometry
bike isn't made for much else other than going hard at it while in the
aero position. Consider this before you adopt this position.
Because of this, there are certain positions that make sense and others
that don't. Besides being in the aero position, there is also an
intermediate position that I sometimes adopt, something not unlike the
"multisport" position described above. I call it a "choke up" position,
and it's adopted by moving very slightly rearward on the saddle, choking
up a few inches on the extensions, and sitting slightly up. While in
this position you'll be able to generate a bit more peak power, and you
might benefit from getting out of the full aero position now and then.
Riding entirely out of the saddle is also a usable position, and riding
in the pursuit position is fine for descending and cornering. What I
often see, but do not at all like, is a sitting-up position with the
hands on the armrest pads while seated climbing. The hip angle is now
too obtuse, and this is a low-cadence, low-power position. Better to
climb either in the aero position, perhaps in the choke-up position, or
out of the saddle. Never sitting entirely up.
• This style of riding trades high-torque riding for even-powered
riding. You won't be able to generate the sort of peak torque in the
aero position that you will while in the road position. Your overall
power will be the same, but your ability to mash a low cadence, or to
accelerate, will be compromised. Therefore, it is imperitive to keep
one's cadence up, probably in the 90-100rpm range. It's quite acceptable
to climb while in the aero position. You'll be surprised how fast you
can climb, although you might not think you're climbing fast unless
you're comparing yourself to others of equivalent ability, or your own
previous times recorded up a fixed ascent. But you will be able
to climb fast. This assumes, though, that you really do keep your
cadence up, and this is a discipline that is hard to learn.
If you think about this, a couple of equipment changes appear rational.
First, if it's so important to keep your cadence up, it's important to
keep your shifters close to your hands. Therefore, bar-end shifting is a
very good idea for steep-geometry riding. Secondly, make sure you've got
the appropriate gears at your disposal. I'm usually riding 53X39 and
12-27 on my 700c-wheeled bike. On a hilly course I've been in my 39-27,
spinning up a hill in the aero position, next to a person climbing out
of the saddle in his big chain ring. If that gentleman outruns me it
won't be because he was a wiser tactical rider.
"Why?" you might ask, "is it preferable to trade in a high-torque
position (riding a 73-degree seat angle bike) for a low-torque
position?" Because you don't want to recruit fast-twitch fibers during
the bike ride. You don't want to use muscles that burn glycogen at a
higher rate. This issue is what separates road riders from triathletes.
This is why triathlon is its own sport, and why you can't necessarily
emulate what you see in the grand tours, even the grand tour time
trials. If you don't have to run off the bike you don't have to worry
about the metabolic cost of your bike ride. If you're reading this, it's
likely that running is in your future.
• This position is most comfortably ridden under effort. The more
you're rotated forward and low in front, the more you're riding on
points on your trunk that don't have much padding. When you're riding in
this position under very low effort, the weight is transfered off the
pedals and onto the saddle. Therefore—though it sounds
counter-intuitive—the lesser your effort level while in the aero
position, the less comfortable your crotch. This doesn't mean you can't
ride your tri bike during easy, recovery rides. It just means it's not
optimized for that. If you have a road race bike, this is usually a
better choice for recovery riding.
Don't take this to mean that a steep-geometry position is unusable for
all kinds of riding. It's usable, just not optimal, for all kinds of
riding. Likewise, road bikes aren't optimal for all kinds of riding, but
they're often used in triathlons anyway. It's just a question of what
sort of riding is most important to you, and then adopting not only the
most appropriate bike position, but the tactical and technical riding
styles that dovetail with that position. When I hear, "I tried a
steep-angled bike but I found I just couldn't generate enough power," I
find that in most cases it was because the rider didn't understand how
steep geometry bikes need to be ridden. He rode his tri bike around town
at 70rpms. Of course he couldn't generate enough power.
Article written by Dan Empfield